97' BMW Z3 chk eng light code 1423

You can find the oil life monitor reset procedure here

Oil Change Light Reset BMW Z3 1998 1999 2000 2001 2002 Reset Your Oil...

1st when the airbag light is on the system is disabled, so if u have an accident they will not work, as to the common cause read below.
When the airbag light is on it means a fault has occurred in the system and the airbag diagnostic monitor has disabled the system, the most common problem that turns the light on is a break in the connection to the steering wheel mounted airbag, this is due to a rotating ribbon contact that breaks under the steering wheel that connects the airbag to the wiring harness and the diagnostic monitor, the part is called th clock spring contact, a coiled up ribbon electrical contact that turns with the wheel

This is the most common problem on these engines that will cause every issue you just mentioned.

Your mechanic did a good test by externally adding more fuel to the engine. The fact that the addition of the extra fuel to the engine changed the engines behavior would suggest he is on the right track.

That sounds like you bought big problems. Oil ights indicate low oil pressure= BIG BUCKS. I would have a qualified repair shop check it out, A shop that specializes in BMW. If you are lucky, maybe the oil sender is just bad. They can also check out the Ck eng light. But the oil light is priority one.

P1143 Air assist control valve range/performance

Could Be your mass air flow sensor. Start there.

It looks like misfiring in one cylinder. That is why check engine come on. Misfiring can be due to spark plugs/wiring/worn distributor cap. Maybe also vaccum leak and clogged injectors (use injector cleaner).
You can read the trouble codes at Autozone store for free
Please kindly let me know if this infor was usefull for you or you need more infro
Good Luck

idle control valve,replace, low oil pressure maybe check level,eml light on,if not get plugged in and aquire fault codes.

this may be your egr valve, does it want to stall when its ticking over.

I have a replacement roof for my 1997 BMW Z3, could anyone give me advice how easy or hard its and could one man do it on his own?